While operating an aircraft, a flight crew must often access one or more checklists within a quick reference handbook (QRH) in order to successfully perform their primary tasks. Because the operation of an aircraft can depend upon the proper use of a QRH checklist, it is highly desirable to provide an improved format for QRH checklists that allow for even safer aircraft operation.
Pilots work in a complex multitasking environment where many things compete for their attention. Since pilots, as do all humans, have limited attention and cognitive resources, these resources have to be distributed to the activities in which they are engaged. If one task requires a lot of the pilots' resources, then their resources may not be available for other tasks.
To successfully perform their primary tasks, crews must perform secondary or “interface management tasks”, such as physically manipulating a checklist, trying to determine what aspects of a checklist should be used in the current task, and/or accessing information in a checklist that is not readily available. In part, these secondary tasks are necessitated by the fact that crews view only a small amount of information at any given time through their flight deck displays and checklist pages.
In many human performance domains, interface management demands have been found to be excessive under some circumstances and the additional workload may interfere with a crew's ability to perform their primary tasks. Two effects have been identified, namely resource-limited effect and data-limited effect. Regarding the resource-limited effect, interface management tasks draw cognitive resources (e.g., attention, etc.) away from the primary tasks and performance declines because there are insufficient resources available for them. With the data-limited effect, primary tasks consume most of the cognitive resources leaving little for interface management performance. Since the primary tasks are dependent on interface management tasks to access the proper information, performance declines due to lack of information.
With respect to the resource-limited effect, primary task performance declines when too much attention is directed to secondary tasks. With respect to the data-limited effect, pilots manage workload by prioritizing their tasks into primary and secondary tasks. Interface management tasks are not prioritized as highly as primary tasks and sometimes are not performed. Crews will use several strategies to minimize interface management demands, such as using the currently viewed information rather than trying to retrieve the best information for the task.
Thus, interface management tasks may create barriers between crews and information. During periods of high workload, crews may decide to not access additional information because the retrieval effort may detract from the crew's primary task of handling the aircraft. Also, seeking new information may disrupt ongoing tasks or may interfere with current information being used. In some cases, crews may not access information because they do not know that it exists, such as failing to use a checklist for annunciated situations.
In summary, while checklists support the general cognitive activities of crewmembers, their use may also add to overall workload and draw resources away from the primary tasks. As noted above, the management strategy adopted by pilots to cope with this added workload can impact performance of the primary tasks.